Home networking is evolving into an environment in which people will be sharing photographs, music, video, data and voice among networked consumer electronics, personal computers and mobile devices throughout the home. Consumers will be able to stream video content from a personal computer or electronic device to flat panel high-definition television (HDTV) without the use of wires. A technology being implemented for enabling these capabilities is ultra wideband (UWB). UWB is a wireless technology designed for short-range, personal area networks.
FIG. 1 shows an example of an indoor broadband wireless communication network. The network includes, for example, a high definition television (HDTV) monitor 110 networked with other devices, such as, a digital video recorder (DVR) 120, a digital video disk (DVD) player 140 and a computing device 130.
HDTV streaming video requires large bandwidths of information. Therefore, the networking of devices that include streaming HDTV must be capable of handling high bandwidths. Additionally, the devices of the network must be resistant to both self-interference and interference from other wireless communication signals. UWB wireless signals operate at very low power levels, making resistance to interference more difficult.
Networking of multiple UWB devices 110, 120, 130, 140 requires the UWB devices 110, 120, 130, 140 to be synchronized so the transmission between the devices 110, 120, 130, 140 can be coordinated. Receiving devices and transmitting devices must know when data transmission between the devices will occur. The scheduling of the data transmission is generally performed through media access control (MAC) scheduling. The transmission occurs during data exchange periods of superframes of the UWB devices. To properly operate, the data exchange periods of the superframes of the UWB devices must be synchronized. Synchronization can be difficult because crystals within the wireless devices that generate clock signals typically drift. Improving (increasing) the accuracy of the crystals can be very expensive.
The superframes of each wireless device 110, 120, 130, 140 are divided into slots of fixed duration. MAC control information is exchanged through the transmission and reception of beacons in a contention-free manner during initial slots in the superframe. The remaining slots are available for the exchange of data. The protocol allows each device 110, 120, 130, 140 to use beacons to reserve specific slots for data transmission without contention. The superframes of each wireless device 110, 120, 130, 140 need to be synchronized so that data transmission between the devices 110, 120, 130, 140 occurs at expected times. A lack of proper synchronization between the devices can cause a loss of transmission data, or undesirably slow the transmission of data.
It is desirable to improve or enhance synchronization of wireless devices of a network without requiring expensive improvements in the performance of crystals within the wireless devices that generate clock signals within the wireless devices.